Modeling the impact of climate change on runoff and annual water balance of an Arctic headwater basin

摘要

Climate change will be an important issue facing Arctic areas in the coming decades since climate models are projecting warmer and wetter conditions for many northern regions. From a hydrological perspective, critical issues include a shortened snow cover season, changes in winter snow cover properties, and changes in the timing and volume of snowmelt runoff. To assess the impacts of projected temperature and precipitation changes on the hydrology of a small Arctic headwater basin, the distributed hydrological model WATFLOOD was used in conjunction with selected Global Circulation Models (GCMs) and future climate scenarios. It was found that the hydrological model simulated basin runoff adequately either with input climate data collected in the study area or with input data from a long-term climate station located approximately 50 km south. WATFLOOD was then used to predict future runoff using GCM outputs for the 2040– 69 and 2070–99 time periods. The results gave dates of first and peak runoff that were, on average, up to 25 days earlier than in current (1961–90) climate. In addition, future runoff and evaporation volumes increased by up to 48% as a result of projected increases in temperature and precipitation. Furthermore, a large number of simulated years showed midwinter melt periods, which will have major impacts on snowpack properties and, in turn, on human, animal, and plant life in this region.